Fixes#36968, updating `libpqxx` to 7.9.0.
No feature needs to be tested.
- [x] Changes comply with the [maintainer
guide](https://github.com/microsoft/vcpkg-docs/blob/main/vcpkg/contributing/maintainer-guide.md).
- [x] SHA512s are updated for each updated download.
- [ ] ~~The "supports" clause reflects platforms that may be fixed by
this new version.~~
- [ ] ~~Any fixed [CI
baseline](https://github.com/microsoft/vcpkg/blob/master/scripts/ci.baseline.txt)
entries are removed from that file.~~
- [ ] ~~Any patches that are no longer applied are deleted from the
port's directory.~~
- [x] The version database is fixed by rerunning `./vcpkg x-add-version
--all` and committing the result.
- [x] Only one version is added to each modified port's versions file.
---------
Co-authored-by: Sam Barrett <s.barrett@qed-analytics.co.uk>
* [many ports] call vcpkg_fixup_pkgconfig()
The ports generate pc files, but don't call vcpkg_fixup_pkgconfig() so that there are absolute paths in the pc files
* Update port-version for armadillo and polyclipping.
* Update version database.
Co-authored-by: Billy Robert O'Neal III <bion@microsoft.com>